1. Field of the Invention
This invention relates generally to bushing devices and relates more particularly to a self-boring bushing device that is threaded directly into a wall structure, thus providing a communicating passage between each side of the structure.
2. Description of the Prior Art
Various auxiliary bushing devices have been proposed for use in providing a communicating passage through different types of structures. However, as is well known in the art, many problems and difficulties are encountered in providing a suitable means for allowing conduits to be passed from one side of a structure to another, particularly with respect to electrical conduits, lead-in wires, and cables.
Generally, entrance bushings are designed for specific purposes and cannot be used for a wide range of installations.
As an example of the various designs and uses that have been disclosed, the following are presented of interest thereto.
U.S. Pat. No. 3,666,878 has disclosed an entrance bushing for an electric treater subject to high voltage, temperature, and pressure-operating conditions. Thus, it is very limited in its use. In addition, special tools are needed to mount this device.
U.S. Pat. No. 1,956,869 illustrates another type of device used to permit passage of an electrical conductor. However, no means are provided wherein the connection is capable of forming its own bore through the accommodating structure in which it is to be mounted.
A conductivity cell is disclosed in U.S. Pat. No. 2,939,070. Here, again, the device is restricted in use and also is not provided with features wherein the body of the device can form its own mounting bore.
Also of interest in the area of bushing fixtures and seals, are U.S. Pat. Nos. 3,322,890 and 3,728,584, but neither provides a self-tapping screw or bolt for use in the general construction industry as a stuffing box, a lead-in, or a conduit fitting.